Roof vent structure



Oct. 28, 1958 r J. H. CARR 2,357,337

ROOF VENT STRUCTURE I Filed Aug. 10, 1956 3 Sheets-Sheet 1 INVENTOR. John H Carr LCKHUFF 5 SZ/CK, iffy:

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Oct. 28, 1958 J'. H. CARR 2,857,837

- ROOF VENT STRUCTURE Filed Aug. 10, 1956 3 Sheets-Sheet 2 INVENTOR. John H. Carr B Y W 14 membero/f/rc firm.

Oct. 28, 1958 J, CARR 2,857,837

ROOF VENT STRUCTURE Filed Aug. 10, 1956 HI! 5 I I 49 I I f; 43 I v I 57 4 ZA I I 55' EIEI E WE un-:12 llkllai j W ,53-

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INVENTOR' John b. Carr BY X ZemberMMefif/n 5 Sheets-Sheet 3 United States Patent Ofiice 2,857,837 Patented Oct. 28, 1958 ROOF VENT STRUCTURE John H. Carr Mountain View, Calif., assignor to Dura- Vent Corporatiom'a corporation of Delaware Application August 10, 1956, Serial No. 603,442

6 Claims. (Cl. 98-84) This invention relates to a vent cowl structure, and more particularly relates to a metal structure of welded or riveted construction.

Vent cowls or caps are commonly used in connection with vents for exhausting combustion gases, such as from space heaters or water heaters, into the air, and it is highly desirable that such cowls present a minimum impediment to the flow of gases therefrom. It is also highly desirable that such structures function regardless of wind direction and particularly that the cowl not act as an air scoop under any wind conditions, whereby a down draft is produced. A still further desirable feature of vent cowls is that they efiectively exclude rain or other foreign matter from entering the vent, as well as preventing access by birds or small animals.

It is an object of the present invention to provide a vent cowl structure having all of the above desirable features, which is inexpensive to construct and durable.

In the drawings forming a part of this application:

Figure 1 is a perspective view, partly in section, showing a vent cowl made in accordance with one embodiment of the present invention.

Figure 2 is an elevation view of the vent cowl of Figure 1, partly in section.

Figure 3 is a sectional view on the lines 33 of Figure 2.

Figure 4 is a sectional view, similar to Figure 3, showing another embodiment of the present invention.

Figure 5 is a perspective View, similar to Figure 1, showing another embodiment of the present invention.

Figure 6 is an elevation view of the vent cowl of Figure 5.

Figure 7 is a partial Sectional view of a vent cowl showing an alternate method of construction.

Referring now to Figures 1 through 4 by reference characters, the vent structure has a base or coupling section of pipe 5 having a series of indentations 7 for securing the pipe to a flue pipe. Fastened to the pipe 5 is an annular ring 9, which has two down-turned rims, designated 11 and 13. The inner rim 11 serves to fasten the ring 9 to the pipe 5 and may be secured by spot welding, riveting or other suitable means. The ring 9 supports an outer deflector 15 which is concentric with the pipe 5, but of larger diameter. The deflector 15 in turn supports the cap structure 17, which has a generally rounded top, as is illustrated, and a terminal rim 19. The deflector 15 has a series of oblong cut-outs 21 located near the top thereof.

A second annular ring 23 is provided which has an inner rim 25, and an outer rim 27. The rings 23 and 9 are substantially identical, but the rims on the lower ring are turned downward while the rims on the upper ring are turned upward. The rim 27 is fastened to the deflector 15 by suitable means, and the inner' rim 25 supports the inner deflector pipe 29. The upper end of the inner deflector pipe 29 terminates on the same plane as the rim 19. The top of the pipe 29 also terminates a 2 substantial distance below the top of the cap 17, so that gas can freely pass over the top of pipe 29 and out through the perforations 21. The bottom of pipe 29 is spaced from pipe 5 so that gases can pass freely between the pipes 5 and Hand out through the perforations in the rings 9 and 23.

The rings '9 and 23 are provided with a series of per forations so that gas can pass readily through them. The perforations may be in the form of a series of long slots, as is shown at 33 in Figures 1 and 3, or may consist of a series of circular cut-outs, as at 35, in Figure 4. In either event, the openings in the rings 9 and 23 may be oflset from each other, as is shown in the drawings.

In drawings 1 and 2, the lips 11 and 25 of the rings 9 and 23 are shown fastened to the outside of the pipes 5 and 29. In some instances, one or both of the lips 11 and 25 may be fastened to the inside walls of pipes 5 and 29, as is illustrated in Figure 7.

Other variations are possible in the construction of the vent structure of the present invention. Referring to Figures 5 and 6, the single row of perforations 21 in the upper pipe may be replaced by a double row of perforations 41 and 43. Similarly, the single rows of perforations 33 in the rings 9 and 23 may be replaced by the double row of perforations 45 and 47. Further, the perforations of the upper and lower rings may be lined up with each other, as is shown in Figure 5, in contrast with the offset relationship shown in Figure 1.

It is also possible to make the pipes 5 and 29 from a single piece of metal, as is shown in Figures 5 and 6. Here 5 and 29 are replaced by member 49, which has a series of slots 51 cut therein, leaving the connecting members 53 joining the upper and lower pipes.

In addition, the lower pipe 5 or the lower portion of pipe 49, designated 49A, may be provided with a shoulder 55, inwardly directed dimples 57, as well as indentations 7, adapting the vent cowl to be used in conjunction with multiple wall pipes forming the subject matter of a copending patent application.

The various components may be fastened together by suitable means such as Welding or riveting, or may be merely pressed together so that the metal is held under tension. The structure may be strengthened by forming a series of pressed in annular grooves, as at 37, to retain the various parts.

In this manner, I have provided a roof vent structure which is relatively inexpensive and easy to construct, which does not cause down drafts, and which offers a minimum of resistance to the passage of gases from a stack. Independent laboratory tests have shown that the vent cowl of the present invention actually increases the draft in still air over that obtained from a plain pipe. Under the very worst Wind conditions, the vent of the present invention gives a draft equal to of the draft of a plain pipe in still air, while a 70% draft under such conditions is generally considered satisfactory.

I claim:

1. A vent cowl structure comprising a basepipe, a first annular, perforated ring attached to said pipe near the top thereof, an outer deflector of larger diameter than said base pipe supported by said first ring, a second perforated annular ring supported by said outer deflector, said rings being perforated to an extent sufficient to provide unimpeded passage of gases therethrough, said second ring being spaced above said first ring, an inner deflector pipe of substantially the same diameter as the base pipe positioned above and spaced from the base pipe and connected to the second ring, a cap having a down-turned rim supported over the outer deflector and a series of perforations near the top of the outer deflector.

4 2. 'The structure of claim 1 wherein the perforations the inner deflector pipe are connected to each other by in the annular rings consist of a series of slots. a series of spaced members.

3. The structure of claim 1 wherein the perforations in the annular rings consist of a series of round holes. References Cit d i th fil f thi t t 4. The structure of claim 1 wherein the perforations of the first and second annular rings comprise a plurality UNITED STATES PATENTS of rows of slots. 201,641 Androvatt Mar. 26, 1878 5. The structure of claim 1 wherein the top of the 1,162,205 Ashorn Nov. 30, 1915 inner deflector pipe is even with the down-turned rim 1,310,470 Calder July 22, 1919 of the cap. 10 1,354,483 Holland Oct. 5, 1920 6. The structure of claim 1 wherein the base pipe and 2,640,413 Reed June 2, 1953 

